Improvement of the sensitivity by UV light in alcohol sensors using porous silicon layer

A capacitance-type alcohol gas sensor using porous silicon as a sensitive layer is developed to measure low alcohol concentration at room temperature. Although the sensor using porous silicon layer shows some sensitivity at room temperature by large internal surface area, but there is still much room for improvement. In this work, we measured the variation of capacitance of the sensor under illumination of 254 nm UV light. As the result, the increase in the slope was observed, and it is supposed that UV light activates the response of the oriental polarization which has a slow relaxation time for AC field.